1. Field of the Invention
The present invention relates to a nozzle plate member (also referred to as a gas diffusion plate) for supplying fluids in a dispersed manner, and a manufacturing method thereof. More specifically, the invention relates to a film-forming nozzle plate member for dispersing and causing gas to feed and flow out, the gas being used for a film-forming process in manufacturing a semiconductor device or a liquid crystal substrate device, and a manufacturing method of such a nozzle plate member.
2. Description of the Related Art
In the process of manufacturing a semiconductor device or a liquid crystal display substrate, film formation has been carried out by spaying gas to a substrate in the process of chemical vapor deposition (CVD) or the like. In such a film-forming process, each of gases of one, two or more kinds, selected from silane gas, oxygen gas, and so on, is supplied, a plurality of gases are uniformly mixed immediately before the substrate, and then a film is formed on the substrate. In the film-forming process, the dispersed supplying of the plurality of gases must be maintained separately immediately before the gases are reached on the substrate, and each of the gases must be supplied to keep uniform mixing on a substrate surface.
Thus, the inventors examined a conventional nozzle plate like that shown in each of FIGS. 26(a) and 26(b), which was used to disperse gases as fluids in stages and supply them through a number of holes. FIG. 26(a) is a sectional view of a gas supplying nozzle plate, and FIG. 26(b) is a sectional view.
As shown in FIGS. 26(a) and 26(b), the gas supplying nozzle plate is constructed by laminating sheet metal members 40, 41 and 42. The plate metal member 40 includes an A gas path hole 43, its branch 44, and a B gas path hole 47, which are all formed by machining. The plate metal member 41 includes an A gas path hole 45, a B gas path hole 48 and its branch 49, which are all formed by machining. The plate metal member 42 includes an A gas path hole 46 and a B gas path hole 50, which are formed by machining. These plate metal members 40, 41 and 42 are joined together by soldering, electron beam welding or bolt fastening, and then laminated to form a unified body.
In the gas supplying nozzle plate constructed by laminating the metal members 40, 41 and 42, A gas is passed through the path hole 43, branched at the branch 44, and dispersed into a number of flows. Then, the A gas flows out through the path holes 45 and 46 to be supplied to a film-forming region. B gas is passed through the path holes 47 and 48, branched at the branch 49, and dispersed into a number of flows. Then, the B gas flows out through the path hole 50 to be supplied to the film-forming region. Then, the A and B gases are mixed with each other immediately before the substrate to form a film on the substrate.
The gas supplying nozzle plate described above with reference to FIGS. 26(a) and 26(b) can supply gas in a dispersed manner. However, problems have been inherent particularly with respect to sealing, the state of the joined portions of the gas path holes, and so on, in the cases of joining by soldering, electron beam welding, and bolt fastening. Specifically, in the case of joining by soldering, the problems include: a reduction in sealing, which is caused by a pinhole formed by gas entrainment during soldering; a loss of cleanness necessary for semiconductor manufacturing or a liquid crystal substrate manufacturing, which is caused by gas generated from a component such as solder; a loss of dimension or function of the gas path hole, which is caused by damaging the precise and fine gas path hole or the branch, such damaging occurring due to the melting of brazing filler metal during joining; and others. To solve the problem of the damaging the gas path hole caused by the melting of solder during joining, soldering foil was used. However, the use of such soldering foil proved to be costly, because the need to process and dispose the soldering foil to match the shape of the precise and fine gas path hole or the branch resulted in much man-hour. In addition, it was impossible to deal with a temperature of about 400° C. during film formation. This problem occurred because of a limitation placed by a temperature during the film formation.
In the case of joining by electron beam welding, the problems include: the difficulties of securing sealing corresponding to all of a number of precise and fine gas path holes or branches formed in the sheet metal member, and carrying out joining without any hole clogging; the difficulty of manufacturing a large gas nozzle plate because of a limitation placed by the size of a high vacuum chamber, in which electron beam joining is performed; and high costs.
In the case of joining by bolt fastening designed to secure sealing by disposing a gasket, the problems include: a loss of designing freedom satisfying a request made by a user, which occurs because of the need to provide a space for machining and disposing a gasket to match the shape of the precise and fine gas path hole or the branch; high costs caused by much man-hour; and the difficulty of securing complete sealing by the gasket. In addition, heat resistance is a significant matter, particularly since such film formation is often carried out at a high temperature. In this respect, it was difficult to provide sufficient heat resistance by the method using the gasket.
The present invention is directed to a gas supplying nozzle plate, which is constructed by laminating a plurality of metal members having fluid paths formed therein. It is an object of the invention to provide a fluid nozzle plate member capable of providing high sealing at joined portions, and high reliability without any reductions in the functions of highly precise fluid paths and branches even when used in high vacuum or at a high temperature. It is another object of the invention to provide a manufacturing method of such a fluid nozzle plate member.